In this study we expect to correlate the presence and significance of autoimmune phenomena to the presence or absence of specific disease. A number of autoantibodies will be looked for in a large relatively stable aging population mostly over age 70. We will identify populations carrying significant loads of autoantibodies as well as those without any. For one study the groups will be followed for a 5 year period to identify changes of these factors in these populations. Another study will correlate autoantibodies, delayed hypersensitivity tests, bone density measurements, responses to influenza vaccines, "routine" blood studies, physical status, and the development of specific diseases of aging. The measurement of autoantibodies will be done by immunofluorescence, complement fixation, antiglobulin consumption, latex and red cell agglutination and agar diffusion.